I. Field of the Invention
The invention is generally related to biochemistry, physiology, medicine, and the inhibition of genomic instability caused by ionizing radiation, such as computed tomography imaging.
II. Background
Computed tomography (CT) is a powerful medical imaging method employing tomography created by computer processing. However, CT scans have been estimated to produce non-negligible increases in the probability of lifetime cancer mortality, leading to calls for the use of reduced current settings for CT scans. Estimated lifetime cancer mortality risks attributable to the radiation exposure from a CT in a 1-year-old are 0.18% (abdominal) and 0.07% (head)—an order of magnitude higher than for adults—although those figures still represent a small increase in cancer mortality over the background rate. In the United States, of approximately 600,000 abdominal and head CT examinations annually performed in children under the age of 15 years, a rough estimate is that 500 of these individuals might ultimately die from cancer attributable to the CT radiation. The additional risk is still very low (0.35%) compared to the background risk of dying from cancer (23%). However, if these statistics are extrapolated to the current number of CT scans, the additional rise in cancer mortality could be 1.5 to 2%. Furthermore, certain conditions can require children to be exposed to multiple CT scans. Again, these calculations can be problematic because the assumptions underlying them could overestimate the risk.
In 2009 a number of studies appeared that further defined the risk of cancer that may be caused by CT scans (Brenner et al., 2001) One study indicated that radiation by CT scans is often higher and more variable than cited and each of the 19,500 CT scans that are daily performed in the U.S. is equivalent to 30 to 442 chest x-rays in radiation. It has been estimated that CT radiation exposure will result in 29,000 new cancer cases just from the CT scans performed in 2007 (Brenner et al., 2001). The most common cancers caused by CT are thought to be lung cancer, colon cancer and leukemia with younger people and women more at risk. Although CT scans come with an additional risk of cancer (it can be estimated that the radiation exposure from a full body scan is the same as standing 2.4 km away from the WWII atomic bomb blasts in Japan (Nelson, 2009; Semelka et al., 2007), especially in children, the benefits that stem from their use outweighs the risk in many cases (Khamsi, 2007). A number of vitamins and nutritional supplements have been shown to protect the organism when it is exposed to ionizing radiation. However, improved methods for consistently and reproducibly reducing the risk of CT associated radiation are needed.